It can take up to three weeks for mpox to evolve into a disease following exposure, as the incubation period is estimated to be anywhere between five and 21 days, according to Donald Alcendor, PhD, a professor of pathology, microbiology, and immunology at the Vanderbilt University School of Medicine.

The illness typically begins with flu-like symptoms such as fever, chills, and swollen lymph nodes before rashes appear, according to the Centers for Disease Control and Prevention. People usually develop a rash or lesions one to four days after. The lesions will scab and fall off over time.

These symptoms can last from two to four weeks, sometimes even six, Alcendor said, and the duration could be longer for those with underlying health conditions.

How Long Would You Stay Infectious?

People with mpox can spread it to others from the time symptoms start until the rash has fully healed and a fresh layer of skin has formed, according to the CDC.

Close, sustained skin-to-skin contact with rash, lesions, or bodily fluid from someone with the virusContact with respiratory dropletsTouching surfaces or objects (clothing, towels, or bedding) that have been used by someone with mpox

Alcendor said mpox is the most contagious when someone is symptomatic and has an active rash, as the blistering rash contains fluid with high amounts of virus that can be readily transmitted through skin-to-skin contact.

“Identifying infected individuals and quarantining the potentially infected individual for an extended period, such as up to three to four weeks, is critical to controlling the viral spread,” he said.

But not everyone is capable of isolating for weeks at a time. For those who can’t, the CDC recommends keeping all lesions covered, wearing a tight-fitting mask, and avoiding close physical contact or sharing items that have been worn or used. In addition, launder or disinfect used items, clothing, and surfaces that have been touched by a lesion.